The eastern osprey (''Pandion haliaetus cristatus'') is a
diurnal,
fish-eating bird of prey. They live in
Oceania
Oceania (, , ) is a geographical region that includes Australasia, Melanesia, Micronesia, and Polynesia. Spanning the Eastern and Western hemispheres, Oceania is estimated to have a land area of and a population of around 44.5 million ...
at coastal regions of the Australian continent, the
Indonesia
Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania between the Indian and Pacific oceans. It consists of over 17,000 islands, including Sumatra, Java, Sulawesi, and parts of Borneo and New Guine ...
n islands,
New Guinea
New Guinea (; Hiri Motu: ''Niu Gini''; id, Papua, or , historically ) is the world's second-largest island with an area of . Located in Oceania in the southwestern Pacific Ocean, the island is separated from Australia by the wide Torr ...
, and the
Philippines
The Philippines (; fil, Pilipinas, links=no), officially the Republic of the Philippines ( fil, Republika ng Pilipinas, links=no),
* bik, Republika kan Filipinas
* ceb, Republika sa Pilipinas
* cbk, República de Filipinas
* hil, Republ ...
. It is usually sedentary and pairs breed at the same nest site, building up a substantial structure on dead trees or limbs.
The subspecies resides in habitat close to coasts and
estuaries
An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environmen ...
that provide opportunities for fishing. In 2022, it was considered a defunct species by the IOC, due to its low genetic divergences and absence in morphological differences.
The eastern osprey's diet consists mostly of vertebrate fish species. It possesses specialised physical characteristics and exhibits unique behaviour to assist in hunting and catching prey.
Taxonomy
A description as species ''Buteo cristatus'' was published in 1816 by the French ornithologist
Louis Vieillot, which came to be cited as a subspecies or race of a widely distributed species.
The epithet ''cristatus'' is derived from the Latin for 'crested' in reference to the stiff tuft of feathers that extend from the nape.
The subspecific treatment ''Pandion haliaetus cristatus'' distinguishes the crest from other subspecies of ''P. haliaetus'', the name taken from ancient Greek ''haliaietos'' for 'sea eagle'.
Later authors described the regional population as separate species—''Pandion leucocephalus'' Gould, J. 1838 and ''Pandion gouldi'' Kaup, J.J. 1847—or as subspecies—''Pandion haliaetus australis'' Burmeister, K.H.K. 1850 and ''Pandion haliaetus melvillensis'' Mathews, G.M. 1912.
Gould's description identified several characteristics that distinguished his new species from widespread ''Pandion haliaetus'', based on specimens collected in Tasmania, Rottnest Island in the west, and Port Essington; the accompanying lithograph illustrating the species—published in the ''Synopsis'' (1838)
to ''
Birds of Australia
Australia and its offshore islands and territories have 898 recorded bird species as of 2014. Of the recorded birds, 165 are considered vagrant or accidental visitors, of the remainder over 45% are classified as Australian endemics: found now ...
''—was executed by
Elizabeth Gould.
Some authorities maintain a treatment of the 'eastern osprey' population as one of four subspecies of ''
Pandion haliaetus
The osprey (''Pandion haliaetus''), , also called sea hawk, river hawk, and fish hawk, is a diurnal, fish-eating bird of prey with a cosmopolitan range. It is a large raptor reaching more than in length and across the wings. It is brown o ...
'', the only extant species of the genus and family. When specimens and observations of new populations were published in the nineteenth century, many authors described these as new species, revisions around the beginning of the twenty first century began to suggest that status as a full species was warranted.
The
Australian Faunal Directory
The Australian Faunal Directory (AFD) is an online catalogue of taxonomic and biological information on all animal species known to occur within Australia. It is a program of the Department of Climate Change, Energy, the Environment and Water
...
recognises a full species treatment,
citing a 2008 revision that noted
genetic distance
Genetic distance is a measure of the genetic divergence between species or between populations within a species, whether the distance measures time from common ancestor or degree of differentiation. Populations with many similar alleles have s ...
comparable to closely related species of ''
Hieraeetus
The genus ''Hieraaetus'', sometimes known as small eagles or hawk-eagles, denotes a group of smallish eagles usually placed in the accipitrid subfamilies Buteoninae or Aquilinae.
They are medium-sized birds of prey inhabiting Europe, Asia, Af ...
'' and ''
Aquila'' (Wink, ''et al''., 2004
) and minor but consistent distinctions in morphology and plumage colour.
Behavioural differences between the three contentious populations include this species residence at marine habitat, whereas the North American population is found breeding and colonising sites near freshwater.
''
Pandion'', described by the French zoologist
Marie Jules César Savigny
Marie Jules César Lelorgne de Savigny (; 5 April 1777 – 5 October 1851) was a French zoologist.
Savigny was born at Provins. In 1798 he travelled to Egypt with the Emperor Napoleon as part of the French scientific expedition to that country ...
in 1809,
[ is the sole genus of the ]family
Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...
Pandionidae; it is named for a mythic Greek figure known as Pandion. Some arrangements place it alongside the hawks and eagles in the family Accipitridae
The Accipitridae is one of the three families within the order Accipitriformes, and is a family of small to large birds with strongly hooked bills and variable morphology based on diet. They feed on a range of prey items from insects to medium-s ...
—which itself can be regarded as making up the bulk of the order Accipitriformes
The Accipitriformes (; from Latin ''accipiter''/''accipitri-'' "hawk", and New Latin ''-formes'' "having the form of") are an order of birds that includes most of the diurnal birds of prey, including hawks, eagles, vultures, and kites, but not f ...
—or else allied with the Falconidae into Falconiformes
The order Falconiformes () is represented by the extant family Falconidae (falcons and caracaras) and a handful of enigmatic Paleogene species. Traditionally, the other bird of prey families Cathartidae (New World vultures and condors), Sagitt ...
. The Sibley-Ahlquist taxonomy has placed it together with the other diurnal raptors in a greatly enlarged Ciconiiformes
Storks are large, long-legged, long-necked wading birds with long, stout bills. They belong to the family called Ciconiidae, and make up the order Ciconiiformes . Ciconiiformes previously included a number of other families, such as herons a ...
, but this results in an unnatural paraphyletic classification.[
They are known by the common name osprey, or distinguished as the eastern osprey,] other names include fish hawk and white-headed osprey. Gould noted the informal vernacular used after settlement of Australia, the 'Little Fish-Hawk' in New South Wales and 'Fish-Hawk' recorded at the Swan River Colony by John Gilbert; the extant names for the species were ''Joor-jout'' at Port Essington and another in southwest Australia, transliterated from the Nyungar language
Noongar (; also Nyungar ) is an Australian Aboriginal language or dialect continuum, spoken by some members of the Noongar community and others. It is taught actively in Australia, including at schools, universities and through public broadcastin ...
; this latter name has proposed for common use in southwest Australia as ''yoondoordo'' ronounced yoon’door’daw
Description
''Pandion cristatus'', comparable in size as a medium-sized raptor or large hawk, occurs near the coast and large water bodies and is highly adapted to hunt and capture marine animals. The plumage is dark brown on the upper surfaces, and pale at the head and lower parts. The throat is white, a black line extends from this through the eye to a dark patch around the ear, demarcating this from the pale colour at the head. When not in flight, the feathers at the crown form a small crest. The breast is dappled with brownish patches, lacing below the neck, this is darker and more strongly banded in the female. The female of the species also tends to be larger. The wing measurements of the females range from 410 to 478 millimetres, males are 391 to 470 mm. The weight of the female is 1.2 to 1.6 kilograms, males are 0.9 to 1.2 kg. The size range of the black bill is 29 to 35 millimetres, and the upper mandible is acutely hooked. The legs and feet of the species are strong and a light grey or white colour. The pattern of the scales at the tarsus is reticulate
Reticulation is a net-like pattern, arrangement, or structure.
Reticulation or Reticulated may refer to:
* Reticulation (single-access key), a structure of an identification tree, where there are several possible routes to a correct identificati ...
. The irides are yellow. The juveniles resemble adults, although the iris colour is a darker orange-yellow and plumage is distinguishable in multiple and subtle ways.
In flight, the eastern osprey has bowed wings with narrow primary feathers that are angled and separate, giving a fingered appearance to the observer below. The eyes are set toward the front of the head, which along with the neck is proportionally small. The species swivels and cranes its neck while observing its surroundings in a curious and characteristic manner. The osprey resembles the white-bellied sea eagle ''Haliaeetus leucogaster
The white-bellied sea eagle (''Haliaeetus leucogaster''), also known as the white-breasted sea eagle, is a large diurnal bird of prey in the family Accipitridae. Originally described by Johann Friedrich Gmelin in 1788, it is closely related t ...
'', which has similar habitat and range, although the adult size is only that of the larger species' juvenile; the wings of an osprey are sharply angled rather than the up-swept outline of the soaring eagle.
Ospreys differ in several respects from other diurnal birds of prey, toes are of equal length, its tarsi are reticulate, and its talons are rounded, rather than grooved. The eastern and western osprey ('' Pandion'') and owls ( Strigiformes) are the only hunters whose outer toe is reversible, allowing them to grasp their prey with two toes in front and two behind. This is particularly helpful when they grasp slippery fish.[
]
Distribution and habitat
The states and territories of Australia where the species is recorded as occurring are Western Australia
Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to th ...
, the Northern Territory
The Northern Territory (commonly abbreviated as NT; formally the Northern Territory of Australia) is an Australian territory in the central and central northern regions of Australia. The Northern Territory shares its borders with Western Aust ...
, Queensland
)
, nickname = Sunshine State
, image_map = Queensland in Australia.svg
, map_caption = Location of Queensland in Australia
, subdivision_type = Country
, subdivision_name = Australia
, established_title = Before federation
, establishe ...
, New South Wales
)
, nickname =
, image_map = New South Wales in Australia.svg
, map_caption = Location of New South Wales in AustraliaCoordinates:
, subdivision_type = Country
, subdivision_name = Australia
, established_title = Before federation
, es ...
, South Australia
South Australia (commonly abbreviated as SA) is a state in the southern central part of Australia. It covers some of the most arid parts of the country. With a total land area of , it is the fourth-largest of Australia's states and territories ...
and Tasmania
)
, nickname =
, image_map = Tasmania in Australia.svg
, map_caption = Location of Tasmania in AustraliaCoordinates:
, subdivision_type = Country
, subdi ...
, The range is a narrow strip at the coast and offshore islands, although it is occasionally found at open river systems and beyond tidal plains. Visits to inland regions from the north during the wet season may occur in years of heavier rainfall.
On this continent it is mainly sedentary
Sedentary lifestyle is a lifestyle type, in which one is physically inactive and does little or no physical movement and or exercise. A person living a sedentary lifestyle is often sitting or lying down while engaged in an activity like soci ...
, non-migratory, in contrast to the other subspecific populations of ''Pandion haliaetus''. They occur patchily around the coastline, although it is a non-breeding visitor to eastern Victoria
Victoria most commonly refers to:
* Victoria (Australia), a state of the Commonwealth of Australia
* Victoria, British Columbia, provincial capital of British Columbia, Canada
* Victoria (mythology), Roman goddess of Victory
* Victoria, Seychelle ...
and Tasmania
)
, nickname =
, image_map = Tasmania in Australia.svg
, map_caption = Location of Tasmania in AustraliaCoordinates:
, subdivision_type = Country
, subdi ...
.[ There is a gap, corresponding with the coast of the ]Nullarbor Plain
The Nullarbor Plain ( ; Latin: feminine of , 'no', and , 'tree') is part of the area of flat, almost treeless, arid or semi-arid country of southern Australia, located on the Great Australian Bight coast with the Great Victoria Desert to its ...
, between its westernmost breeding site in South Australia
South Australia (commonly abbreviated as SA) is a state in the southern central part of Australia. It covers some of the most arid parts of the country. With a total land area of , it is the fourth-largest of Australia's states and territories ...
and the nearest breeding sites at the southwest of Australia.[
The species had been reported as uncommon in the southeast of Australia.
Other regions inhabited by the species at the ]Philippines
The Philippines (; fil, Pilipinas, links=no), officially the Republic of the Philippines ( fil, Republika ng Pilipinas, links=no),
* bik, Republika kan Filipinas
* ceb, Republika sa Pilipinas
* cbk, República de Filipinas
* hil, Republ ...
, Indonesia
Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania between the Indian and Pacific oceans. It consists of over 17,000 islands, including Sumatra, Java, Sulawesi, and parts of Borneo and New Guine ...
and New Guinea
New Guinea (; Hiri Motu: ''Niu Gini''; id, Papua, or , historically ) is the world's second-largest island with an area of . Located in Oceania in the southwestern Pacific Ocean, the island is separated from Australia by the wide Torr ...
. Seasonal visitors to Sulawesi arrive from the south, and these are presumed to have migrated from the north of Australia.
The tree selected as a roost or nest site in Australia is a large eucalypt. They may be seen in flight over a variety of habitats occurring between their residence and hunting waters.
Behaviour
The species is solitary or paired with a breeding partner, the association of several individuals in family groups are unusual records. They are a diurnal species, ranging out from a nest or perch over water bodies during daylight, but have been recorded hunting at night. Their flight may be high, soaring over and surveying the water, or quartering closer to the surface; some flight is seemingly unrelated to hunting.
Hunting
The diet is largely local species of fish, although a favoured target in Australia is known to be mullet when available. Occasional records are given for other marine life—sea snake
Sea snakes, or coral reef snakes, are elapid snakes that inhabit marine environments for most or all of their lives. They belong to two subfamilies, Hydrophiinae and Laticaudinae. Hydrophiinae also includes Australasian terrestrial snakes, wher ...
s, molluscs and crustaceans—and for terrestrial species of reptiles, insects, birds and mammals. They are known to capture sea birds in flight.
Ospreys have vision that is well adapted to detecting underwater objects from the air. Prey is first sighted when the eastern osprey is 10 to 40 metres above the water, after which the bird hovers momentarily then plunges feet first with wings raised; a large splash is made as it enters the water. The descent toward their prey may be done in stages, and they may immerse themselves up to a depth of 1 metre. After seizing their target they use heavy wing beats to rise from the water's surface, resuming a regular action with the fish being carried head first toward the shore. The prey is "slung torpedo-fashion" with a leading foot behind the head and the other clasping behind, this aligning habit distinguishes ''Pandion'' from indifferent clutching of prey by fishing eagles. Their large prey is not swallowed immediately, instead being butchered at a perch or nest site outside the breeding season.
The genus ''Pandion'' has several adaptations that suit its piscivorous
A piscivore () is a carnivorous animal that eats primarily fish. The name ''piscivore'' is derived . Piscivore is equivalent to the Greek-derived word ichthyophage, both of which mean "fish eater". Fish were the diet of early tetrapod evoluti ...
lifestyle, these include reversible outer toes, sharp spicules on the underside of the toes,[ closable nostrils to keep out water during dives, and backwards-facing scales on the talons which act as barbs to help hold its catch.
The osprey has dense plumage which is oily and prevents its feathers from getting waterlogged.]
Reproduction
Rocky outcrops just offshore are used in Rottnest Island
Rottnest Island ( nys, Wadjemup), often colloquially referred to as "Rotto", is a island off the coast of Western Australia, located west of Fremantle. A sandy, low-lying island formed on a base of aeolianite limestone, Rottnest is an A-class ...
off the coast of Western Australia
Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to th ...
, where there are 14 or so similar nesting sites of which five to seven are used in any one year. Many are renovated each season, and some have been used for 70 years. The nest is a large heap of sticks, driftwood, turf or seaweed that is usually built in the fork of a dead tree or limb, cliff faces are also utilised. trees, rocky outcrops, utility poles, artificial platforms or offshore islets.[ Continually occupied nest structures may reach up to two metres in height.] Nests can be as wide as 2 meters and weighing about 135 kg.
Generally, eastern ospreys reach sexual maturity and begin breeding around the age of three to four years.
Eastern ospreys usually mate for life, although polyandry
Polyandry (; ) is a form of polygamy in which a woman takes two or more husbands at the same time. Polyandry is contrasted with polygyny, involving one male and two or more females. If a marriage involves a plural number of "husbands and wives ...
has been recorded in several instances.[ The breeding period varies according to local seasons: this begins between September and October in southern Australia, April to July in northern Australia and June–August in southern Queensland.][ In spring the pair begins a five-month period of partnership to raise their young. The clutch size is usually two to three ]eggs
Humans and human ancestors have scavenged and eaten animal eggs for millions of years. Humans in Southeast Asia had domesticated chickens and harvested their eggs for food by 1,500 BCE. The most widely consumed eggs are those of fowl, especial ...
, sometimes up to four, and are able to brood twice in a season. These are laid within a month, and relies on the size of the nest to conserve heat. The egg shell is white or buff with bold splotches and spots of reddish-brown, sometimes so dark as to be black; purple or grey blotches may appear beneath the surface of the shell. The egg measurements are about 62 x 45 millimetres and weigh about 65 grams.[ The eggs are incubated for about 35–43 days to hatching.][Poole, Alan F. ''Ospreys, A Natural and Unnatural History'' 1989]
The newly hatched chicks weigh 50 to 60 grams and fledge in 8 to 10 weeks. A study on Kangaroo Island
Kangaroo Island, also known as Karta Pintingga (literally 'Island of the Dead' in the language of the Kaurna people), is Australia's third-largest island, after Tasmania and Melville Island. It lies in the state of South Australia, southwest ...
had an average time between hatching and fledging of 69 days. The same study found an average of 0.66 young fledged per year per occupied territory, and 0.92 young fledged per year per active nest. Some 22% of surviving young either remained on the island or returned at maturity to join the breeding population.[ When food is scarce, the first chicks to hatch are most likely to survive. The typical lifespan is 7–10 years, though rarely individuals can grow to as old as 20–25 years.
A nest examined in 1902 found fish skeletons at the edge and a seaside plant 'pig-face' ('']Mesembryanthemum
''Mesembryanthemum'' is a genus of flowering plants in the family Aizoaceae; like many members of this family, it is characterized by long-lasting flower heads. Flowers of ''Mesembryanthemum'' protect their gametes from night-time dews or frosts ...
'') in full growth.
Status and conservation
There is evidence for regional decline in South Australia where former territories at locations in the Spencer Gulf and along the lower Murray River
The Murray River (in South Australia: River Murray) (Ngarrindjeri: ''Millewa'', Yorta Yorta: ''Tongala'') is a river in Southeastern Australia. It is Australia's longest river at extent. Its tributaries include five of the next six longest ...
have been vacant for decades.[
Nesting sites on the ]Eyre Peninsula
The Eyre Peninsula is a triangular peninsula in South Australia. It is bounded by the Spencer Gulf on the east, the Great Australian Bight on the west, and the Gawler Ranges to the north.
Originally called Eyre’s Peninsula, it was named af ...
and Kangaroo Island
Kangaroo Island, also known as Karta Pintingga (literally 'Island of the Dead' in the language of the Kaurna people), is Australia's third-largest island, after Tasmania and Melville Island. It lies in the state of South Australia, southwest ...
are vulnerable to unmanaged coastal recreation and encroaching urban development.[
In New South Wales, the osprey is a protected species. For this reason, ]conservation
Conservation is the preservation or efficient use of resources, or the conservation of various quantities under physical laws.
Conservation may also refer to:
Environment and natural resources
* Nature conservation, the protection and managem ...
ists cannot move a nest of ospreys from the bottom left light tower of Central Coast Stadium
Central Coast Stadium (known originally as Grahame Park), known commercially as Industree Group Stadium is a sports venue in Gosford, on the Central Coast of New South Wales, Australia. The stadium is home to the Central Coast Mariners asso ...
.
The conservation status in Western Australia is as 'not threatened', relatively common in the North and less frequently recorded in the south. A 1902 report by Alexander Milligan of a breeding pair in the southwest region was published in ''The Emu
''Emu'', subtitled ''Austral Ornithology'', is the peer-reviewed scientific journal of BirdLife Australia (formerly the Royal Australasian Ornithologists Union). The journal was established in 1901 and is the oldest ornithological journal publ ...
'', and a description of a nest with two eggs located at Cape Mentelle
Cape Mentelle is a limestone headland on the Indian Ocean coast of south-western Western Australia. It is within the Leeuwin-Naturaliste National Park, just north of the mouth of the Margaret River and west of the town of Margaret River. It ...
which had been photographed eleven years earlier by A. J. Campbell. One egg was taken for deposit at the state's museum by Milligan and along with the museum's director, B. H. Woodward, charged the warden of the cave system with protection of the site.
The species is rare in Victoria and now absent from Tasmania.
References
*
External links
{{Taxonbar, from=Q2880614
eastern osprey
Birds of Oceania
eastern osprey
eastern osprey